Electric welding ground



M A R B R 0 ELECTRIC WELDING GROUND Filed Nov. 12, 1943 t INVENTOR. Olyverliflflbram ATTORNEYS Patented Mar. 9, 1948 "UNITED STATES PATENT OFFICE 2,437,633 ELECTRIC WELDING GROUND Oliver R. Abram, Glendale, Calif.

Application November 12, 1943, Serial No. 510,063

'1 Claim. (01. 173-324) My invention relates to electric welding, and has among its objects and advantages the provision of an improved magnetic ground for direct current arc welding devices.

In the accompanying drawings:

Figure 1 is a perspective view of my invention.

Figure 2 is a longitudinal sectional view.

Figure 3 is a bottom view, and

Figure 4 is a diagrammatic view of the electric circuit.

In the embodiment of the invention selected for illustration, I make use of an electromagnet I of the horseshoe type for coaction with the work l2. This magnet is attached to the top wall [4 of a, metal case I 6 which is open at its bottom end. A sheet of insulation I8 is interposed between the magnet I0 and the top wall 14, and the magnet is made secure by screws i9 which are insulated from the case 16. The magnet isiormed of laminated iron.

A steel pin 20 is slidably guided in insulatin wall by a bushing 60. To the terminal screw 58 i is connected one end of a wire 62 leading to a coil 64 on one leg of the magnet l0.

A second wire 66 leads from the coil 64 and through an opening 68 in one of the plugs 42 for connection with a toggle switch 10 mounted inside the handle 38. An insulated wire 12 leads from the toggle switch 10 to the electrode side of the welding machine 46. The wire 14 in Figure 4 with the work.

bushings 22 supported in arms 24 attached to 1 the magnet ID by screws 26. An opening 28 is provided in the wall M to loosely accommodate the pin 20, and the lower end of the pin is provided with a hardened steel point 30 of tapered contour and adapted for engagement with the work l2. Upon the pin 20 is mounted a coil spring 32 having one end abutting the uppermost bushing 22 and its other end abutting a washer 34 on the pin and resting on a key 36 attached to the pin 20. Thus the pin 20 is slldably guided by the arms 24 and is yieldingly biased against the work l2.

A tubular handle 38 is provided with a lip 40 spot welded to the wall l4, and insulating plugs 42 are secured in both ends of the handle.

A ground wire 44 extending from the welding machine 46 extends throughopenings 48 in the plugs 42 and connects with a clip 50 mounted on the pin 20. This clip is interposed between a lock nut 52 threadedly connected with the pin 20 and a cap nut 54 threadedly connected with the upper end of the pin. A short wire 56 is interposed between the clip 50 and lock nut 52 and connectswith a, terminal screw 58 extending through the lip 40, the wall l4 and the insulation l8, but the terminal screw is insulated from the lip and the Without further elaboration, the foregoing will so fully explain my invention, that others may, by applying current knowledge, readily adapt the same for use under various conditions of service.

I claim:

In an electric welding apparatus comprising a housing having an open bottom, a horseshoe type electromagnet carried interiorly of the housing and extending below the bottom thereof, guide arms carried by one side of the electromagnet, a contact pin vertically movably supported in said guide arms, insulated bushings carried by said arms to insulate said pin from said arms and said electromagnet and a, spring acting on said pin for yieldingly holding it in contact with the work.

OLIVER R. ABRAM.

REFERENCES CITED .The following references are of record in the file of this patent:

UNITED S'IA'I'ES PATENTS Number Name Date 1,249,430 Lewis Dec. 11, 1917 1,292,296 Freese Jan. 21, 1919 2,170,287 Kinnebrew Aug. 22, 1939 2,287,112 Lourie June 23, 1942 2,312,083 Doane Feb. 23, 1943 2,345,630 Ringwald Apr. 4, 1944 

